Not familiar with your printer but found this on the web...
When you do the Canon Print Head Test & you get all of the solid colors & solid (black & lite black) bars, that is CLI 8 Black that you are getting, NOT the PGI Black. If the PGI Black was working, you would get a little graph of horizontal & vertical lines showing at the very top, the very first line of print from the test. PGI Black prints all black text. CLI 8 Black prints photos.
Its most likely a lack of ink, or a blocked print head. If you ran out of ink and left it for a couple of days, what was left in the printhead could have dried and blocked the head.
If what you are trying to print is set to use the black cartridge only and its blocked you will get this effect. If you have the option, try getting it to print without using the black cartridge in which case it should produce black by mixing inks from the colour cartridges but as mentioned I am not familiar with your printer, so dont know.
Sorry but cant help further.